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sb stroker carb recommendations???

Posted By: 70challenger408

sb stroker carb recommendations??? - 03/08/10 02:11 AM

Just got done with the sb 408 upgrades. I changed heads/cam/torque converter. the heads are ootb indybrocks, 1.5/1.6 rockers. cam is Comp solid roller 248/254 @ .50", 616/582 lift. tq is a reworked dynamic 9.5 with 4100 stall. Just got it all up and running, but seems like carb problems(currently has a 750 mighty demon). runs real rich, and has idle problems. is the carb too small???? what are you guys using for sb 408 strokers??? trying to get this ready for mopars at the strip.
Posted By: dartman366

Re: sb stroker carb recommendations??? - 03/08/10 02:18 AM

I run a 1050 dominator on mine, list 9375 and it work's real well, if you want to stay with a 4150 style then get a 950 or a custom 1050, those 408's like a lot of manifold plenum and a big carb.
Posted By: 70challenger408

Re: sb stroker carb recommendations??? - 03/08/10 02:21 AM

I have a victor 340 intake on the engine right now. I also found a mighty demon 850 in the garage, think i should swap to that?
Posted By: dartman366

Re: sb stroker carb recommendations??? - 03/08/10 02:32 AM

Yes,, as long as it is a known good carb.
Posted By: MR_P_BODY

Re: sb stroker carb recommendations??? - 03/08/10 02:41 AM

Quote:

Just got done with the sb 408 upgrades. I changed heads/cam/torque converter. the heads are ootb indybrocks, 1.5/1.6 rockers. cam is Comp solid roller 248/254 @ .50", 616/582 lift. tq is a reworked dynamic 9.5 with 4100 stall. Just got it all up and running, but seems like carb problems(currently has a 750 mighty demon). runs real rich, and has idle problems. is the carb too small???? what are you guys using for sb 408 strokers??? trying to get this ready for mopars at the strip.




I know of a few that have had problems with Demons
specially on idle... I believe a 750 is too small
for your 408.... I run a 1050 on my 405ci... but
RPM has something to do with the carb selection
Posted By: jcc

Re: sb stroker carb recommendations??? - 03/08/10 03:14 AM

Not to hijack, but what if a Indybrock 408 similiar cam but for road race with E-85 and 6000rpm max? Throttle response being more important then max output. 750, 850 or 950?
Posted By: MR_P_BODY

Re: sb stroker carb recommendations??? - 03/08/10 03:17 AM

Quote:

Not to hijack, but what if a Indybrock 408 similiar cam but for road race with E-85 and 6000rpm max? Throttle response being more important then max output. 750, 850 or 950?



For throttle response go with a smaller carb like a 750
specially with 6000 max
Posted By: Ian

Re: sb stroker carb recommendations??? - 03/08/10 03:25 AM

i have a 950 pro systems on mine it flows 830 cfm wet ,that's about the same as your 750 ,bg 850 flows a 1000 cfm i can get 1050 domanator thinking of trying this to see if there is any difference next sunday i can post results then
Posted By: DconD100

Re: sb stroker carb recommendations??? - 03/08/10 06:36 AM

My 408 is all done at 6200rpm, and it is actually more throttle responsive with the 1000cfm quickfuel carb than it was with the proform 750! Must have been the tune, but I also picked up 2 tenths with the switch to the bigger carb. (M1 single plan with a one inch Wilson spacer) Also, the increase was observed on pump gas originally, and now still works great with the E85.
Posted By: Crizila

Re: sb stroker carb recommendations??? - 03/08/10 01:15 PM

Quote:

Just got done with the sb 408 upgrades. I changed heads/cam/torque converter. the heads are ootb indybrocks, 1.5/1.6 rockers. cam is Comp solid roller 248/254 @ .50", 616/582 lift. tq is a reworked dynamic 9.5 with 4100 stall. Just got it all up and running, but seems like carb problems(currently has a 750 mighty demon). runs real rich, and has idle problems. is the carb too small???? what are you guys using for sb 408 strokers??? trying to get this ready for mopars at the strip.

Running a very similar set up to yours ( 750 mighty demon annular discharge and idle-eze ). Same rich issues @ idle - could'nt go more than 1/2 turn out with mixture screws before it was way rich. I was told by Grant to change the idle feed restrictors from .036 to .033". Didn't seem to help. I went ahead and opened up the idle-eze air bleed holes about .003 ( all 4 holes ). This seemed to help. I was able to get enough air in to where I could close up the throttle blades a bit and assure I was staying out of the transition slots. I've been thinking about going to a little bigger carb also, but I run a very heavy car and 3500 stall convertor / 4.10 gear and concerned with hurting 60 foots?
Posted By: 77DragracerR/T

Re: sb stroker carb recommendations??? - 03/08/10 01:57 PM

I'm currently running a 750hp carb on mine with pv's blocked and it's very crisp and idles well.590mp cam and Super Victor intake but i'm still looking at purchasing a 950hp stage 7 from BIGS as i feel there's more in that combo with a bigger carb.
Posted By: 70challenger408

Re: sb stroker carb recommendations??? - 03/08/10 04:33 PM

would you guys run a demon, or a QFT. 1050 on the street???
Posted By: emarine01

Re: sb stroker carb recommendations??? - 03/08/10 04:53 PM

Try the bg 850, its a large venturi big plate 850, they can flow 1000 cfm with the small down leg booster, you need to play with all the BG carbs for running rich, they don't adjust the same as as holly's, otherwise the 9375 Holley 1050 works good
Posted By: 70challenger408

Re: sb stroker carb recommendations??? - 03/08/10 05:02 PM

guess that's tonight's project-let you guys know the outcome.
Posted By: AndyF

Re: sb stroker carb recommendations??? - 03/08/10 06:53 PM

I'm putting a Holley 650 main body on this 427 inch small block.
Posted By: DconD100

Re: sb stroker carb recommendations??? - 03/08/10 09:55 PM

I run my 1000cfm Holley (I said quickfuel before, but is a Holley with quickfuel E85 metering blocks) on my truck. Drive it every day...well when the streets aren't covered in snow anyway! I get the same 12mpg I got with the 750.
Posted By: b1dartsport

Re: sb stroker carb recommendations??? - 03/09/10 01:50 AM

Running a race demon rs with the 1050 sleeves in it and annular boosters on my 408. Going to try it with downlegs this year.
Posted By: 69Cuda340S

Re: sb stroker carb recommendations??? - 03/10/10 10:07 PM

For the idle problem you might have a situation where the transfer slots are over exposed. Usually that can be fixed by cracking open the secondaries some which allows the primaries to be closed bringing the throttle plate to transfer slot relationship back where it should be. This usually happens with high duration cams.
Posted By: JUST_N_TIME

Re: sb stroker carb recommendations??? - 03/11/10 03:39 AM

then don't buy a 959 from Biggs. Look at QFT.
Posted By: moper

Re: sb stroker carb recommendations??? - 03/11/10 12:26 PM

I run Street Avenger 870s on them but with a little less cam. With your build Id say go with an HP950 if this is a strett car first and foremost.
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